expect实现自动交互免密登录操作

# 写个用于自动生成密钥对的函数

auto_keygen (){
    /usr/bin/expect<<EOF

    set timeout 30

    spawn   ssh-keygen

    expect     {

        ".ssh/id_rsa)"       { send    "\n";  exp_continue }
        "Overwrite (y/n)?"   { send    "y\n"; exp_continue }
        "no passphrase):"    { send    "\n";  exp_continue }
        "again:"             { send    "\n";  exp_continue }
    }

EOF
}

# 写个自动免密登录的函数
send_key () {
pwd=upsa
/usr/bin/expect <<EOF
set timeout 30

# 发送公钥给对方服务器
spawn ssh-copy-id root@$1
expect {
"yes/no" { send "yes\n"; exp_continue }
"password:" { send "${pwd}\n"; exp_continue } 
}
expect eof
EOF
}

# 定义一个变量，其值是当前用户的公钥文件
pub_key_file=$HOME/.ssh/id_rsa.pub

# 假如公钥文件不存在，说明需要创建密钥对
if [ ! -f ${pub_key_file} ];then
    auto_keygen
fi

# 循环一个存放 ip 地址的文件，并且把每个 IP地址传递给 函数
for ip in $(cat ./ips.txt)
do
   send_key $ip
done